The shining gem of the NonSerialMovie, an antagonist who is inevitably related (especially romantically) in some way to one of the characters. The trouble occurs when they revisit, and the current situation (say, a character's new LoveInterest) is one that doesn't suit them at all. For maximum effect, TheReveal pulled off near the very end gives a little twist to the "villain" as well as some surprising insight to a relevant character. These work well for such a movie because it is much easier to add {{backstory}} without affecting things later, and is often never mentioned again in the television series proper.

[[folder:Anime and Manga]]* Fiore in the first ''Franchise/SailorMoon'' movie. He befriended Mamoru when he was amnesiac and hospitalized, and years late he returned to Earth to meet him again... * Forms the basis of one of the ''Manga/UruseiYatsura'' movies: Ataru made a ChildhoodMarriagePromise to a girl he frequently saw on the playground. Fast-forward ten years, and we discover that not only was she an alien princess (with an entire army at her disposal), she's never realized that the proposal was meant as a joke. Understandably, Lum isn't appreciative of this state of affairs; neither is Ataru, but that's because he isn't getting any tail out of it.* Ukyou was introduced to ''Manga/RanmaOneHalf'' in this role. Specifically, she was Ranma's former childhood friend who wanted to get revenge on Ranma and Genma for stealing her father's okonomiyaki stall many years ago. However, she quickly pulled a HeelFaceTurn and become one of Ranma's suitors.* Sara's long-lost brother Ralph in ''Anime/StrainStrategicArmoredInfantry'' is revealed near the end of the first episode, after the Union has been praising him and Sara herself chasing after him for years, to be the most fearsome villain the series had to offer.* The demonic Duel Monsters card Yubel in ''Anime/YuGiOhGX'' was revealed to have been owned by Juudai back in the day. He didn't forget her on purpose, though, having his memory suppressed due to the nightmares he suffered when she was in pain up in space. * In ''Anime/CodeGeass'''s {{backstory}}, they were best friends, but eight years later, [[KnightTemplar Suzaku Kururugi]] and [[WellIntentionedExtremist Lelouch Lamperouge]] are on opposite sides. Neither is an [[AntiVillain outright villain]]... nor are they [[AntiHero full-blooded heroes]].* Very similar situation in ''Anime/MobileSuitGundamSEED'', which has Athrun Zala and Kira Yamato fighting each other despite having been the best of friends earlier in life (something which causes both massive amounts of {{Angst}}).* Koujirou Saeki from ''Manga/ThePrinceOfTennis'', in regards to the Fuji brothers.* ''Manga/KenichiTheMightiestDisciple'' has [[spoiler: Odin, the leader of Ragnarok, aka Ryuuto Amamiya]], who was one of Kenichi's childhood friends.* Mendou in ''VisualNovel/WhiteAlbum'' has aspects of this, only she is a benevolent, and not a hostile figure (as far as these things can be counted).* In ''Anime/RevolutionaryGirlUtena'', we find out pretty early on in the series that Utena met Touga and Saionji when she was young. Shortly after that, she met Dios. Shortly after ''that''... [[spoiler: she met Anthy]].** Justified in that she only saw the boys once before the series and probably wasn't even paying attention because she very depressed and traumatised [[spoiler: after her parents's deaths]]. In the case of [[spoiler: Anthy]], she was [[spoiler: given LaserGuidedAmnesia.]]* In ''Anime/GhostInTheShellStandAloneComplex'' [[spoiler:Hideo Kuze]] is this to the Major.** In the 2015 ''Anime/GhostInTheShellArise'' [[TheMovie movie]], turns out that [[spoiler: Lt. Col. Kurutsu is actually a young girl whose body failed badly upon receiving cyberization and she's been stuck in a special facility for years. The adult body we see of her is a remote drone. And she was friends with Motoko Kusanagi when she was also a patient at that facility.]]* A variation in ''Manga/PokemonAdventures''. [[spoiler: Ruby and Sapphire]] both remember having a childhood friend, but they don't remember what the other ''looks'' like. As such, they don't recognize each other when they reunite five years later and get off the wrong foot. Justified by the fact that they both had their personalities completely flipped since they were kids.* Makarov, the BigGood of ''Manga/FairyTail'' and master of the titular guild, recognizes Grimoire Heart's master Hades as [[spoiler:Purehito, his predecessor as the master of Fairy Tail]].* Shiroemon in ''Manga/{{Dorabase}}'', who befriended Kuro during their days in school. They broke off the friendship after Shiro refuses to stay as he is (being good at nothing). From what is known from the flashbacks, he believes that nobody can be counted on to succeed by one's self after [[FreudianExcuse what he's been through]]. He is initially presented as a JerkAss, selfish character who openly shows disrespect towards his teammates. However CharacterDevelopment kicks in soon enough and he gets better, and his relationship with Kuro being more rivalry than dislike, but he is still in the [[HeroAntagonist Whiters]], Dora's WorthyOpponent ArchEnemy.* In ''Manga/{{Naruto}}'', the masked man Tobi's identity is revealed as [[spoiler:Uchiha Obito]], the childhood friend of one of the main characters (who was fighting him at the time): [[spoiler: Kakashi Hatake]]. Naturally, the person is so shocked that [[DespairEventHorizon he completely loses his will to fight]] and it takes quite some effort from the others to bring him back on track.[[/folder]]

[[folder: Comic Books]]* ''ComicBook/TheDeathOfClarkKent'': 90s ''Franchise/{{Superman}}'' villain Conduit may have started this as a trend in comic books. An old schoolmate who always felt overshadowed by Clark growing up (with an emotionally abusive father not helping matters), his grudge turns murderous when he figures out the truth and assumes Clark was only better because of his powers.* Tommy Elliot / Hush from ''Franchise/{{Batman}}'' - a childhood friend of Bruce Wayne's who turns out to be the villain behind the arc introducing him. His jealousy of Bruce stemmed from him ''hating'' his parents and envying the "freedom" Bruce received. And, blaming Bruce's father for saving the life of one of his parents, preventing him from being free. ** Another Batman example is Dan Kingdom / "The Enforcer" from the early 70s "Manhunter" arc. Bats finally figures it out (due to an idiosyncratic fighting style) and delivers a pretty savage beatdown while noting that his opponent was completely the Enforcer now and no longer his old friend Dan Kingdom: "The Council may have planted a clone's body to throw us off the trail, but it was still ''you'' who died."* In ''Comicbook/UltimateSpiderMan'', Eddie Brock was Peter Parker's childhood best friend, but moved away after both his and Peter's parents were killed in a plane crash. A home movie causes Peter to remember Eddie and seek him out, which eventually leads to Eddie's transformation into Comicbook/{{Venom}}. [[/folder]]

[[folder:Live Action TV]]* In the season 2 episode of ''Series/BuffyTheVampireSlayer'' "Lie To Me", Billy Fordham--"Ford"--an old friend of Buffy's from LA, shows up in Sunnydale. He has figured out she's a Slayer... and that's just for starters. He makes a deal with vampires to bring them Buffy and some [[VampireVannabe vampire wannabes]] to feed on, so that they will turn him in exchange. He's trying to avoid dying of cancer.** "Conversations With Dead People" had Holden Webster, an old classmate of Buffy's, recently being turned into a vampire. They have a long friendly conversation before fighting to the death.* ''Series/DoctorWho'' has Mels, who grew up with Amy and Rory as their best friend, but whom the Doctor (and audience) have never met before. After she explains she skipped appearing at their wedding, she pulls a gun on the Doctor in order to "[[TitleDrop Let's Kill Hitler!]]" but gets fatally shot during the escapade. [[RunningGag This is where it gets complicated]]... [[spoiler: as Mels begins to regenerate]].** We then get TheReveal that Mels is actually [[spoiler: Amy and Rory's daughter, Melody ([[TimeyWimeyBall named after herself]]), who was kidnapped by the Silence and raised to kill the Doctor. After an unforseen event caused her to regenerate from a little girl at the end of "Day of the Moon", she decided to spend her second incarnation growing up alongside her parents. Which brings us to her newly regenerated third incarnation... River Song, whose future-self both Amy and Rory have met ''many'' times beforehand, and whose name comes from a garbled translation of "Melody Pond".]] [[/folder]]

[[folder:Tabletop Games]]* ''MagicTheGathering'' has Gerrard, hero of the ''Weatherlight'' saga, pitted against Volrath, evil evincar of Rath and Gerrard's jealous adoptive brother from his youth.[[/folder]]

[[folder:Video Games]]* Misha of the first ''[[VideoGame/ArTonelicoMelodyOfElemia Ar tonelico]]'' game spends a good half the game trying to convince [[IdiotHero Lyner]] that she and he grew up together. It takes most of the game before he remembers - and it's up to the player's choice eight hours ago whether or not she's the [[ChildhoodFriendRomance Unlucky Childhood Friend or Victorious Childhood Friend]] (barring going for the secret LoveInterest...)* ''VideoGame/RuleOfRose'', [[spoiler:with Wendy, where she wasn't even forgotten; her best friend had merely got a new dog. Wendy was so afraid of losing Jennifer [[{{Yandere}} that this gave her reason to resort to blackmail, bullying and eventually murder to bring them back together.]]]]** More literally, [[spoiler:everyone, especially Brown. When Jennifer was found after the massacre, she had amnesia, and only remembered years later.]]* In ''VideoGame/EpicMickey'', Oswald the Lucky Rabbit is Mickey Mouse's older half-brother who was lost to Walt Disney over a legal dispute and replaced by Mickey himself. Judging from what information we have on the game now, it's not going to be pretty when he and Mickey first meet.* ''VideoGame/{{Persona 2}}: Innocent Sin'': [[spoiler:While everyone else in the "Masked Circle" group suffers from ForgottenFirstMeeting, the last member, Jun, still does remember that they nearly killed TeamMom Maya and built up a grudge after forgetting the "nearly" part... and became the enemy known as the Joker for the first 3/4ths of the game.]]* Used in ''VideoGame/FinalFantasyVIII'' when it's revealed that all of the SEED members in the main party had grown up together in the same orphanage, but most of them had forgotten. A JustifiedTrope, as amnesia is an established side effect of letting Guardian Forces take up space in the user's brain.* ''VideoGame/SoulNomadAndTheWorldEaters'' state that [[spoiler:Lobo]], one of the villains was this to [[spoiler:Christophe]], with this being a big part of the former's StartOfDarkness. This plays a part in [[spoiler:The Demon Path, where if Revya states that s/he trusts him, he bursts into maniacal laughter and states that only fools trust]].* In ''VideoGame/FireEmblemFates'', one of the characters that joins the group no matter what path is taken is the Avatar's childhood friend, Silas. In the ''Birthright'' and ''Revelations'' paths, however, the group has to fight him before he joins. Either way, the [[PlayerCharacter Avatar]] initially doesn't remember him, since he was banished from the Nohr castle several years ago for taking him/her outside. [[spoiler:Reaching A-Support with him reveals that the servants and retainers did their best to make the Avatar forget Silas so they wouldn't cry about missing him.]][[/folder]]

[[folder:Visual Novels]]* Shiki doesn't remember [[spoiler:SHIKI]], the BigBad in ''VisualNovel/{{Tsukihime}}'', due to some LaserGuidedAmnesia.* In ''VisualNovel/DengekiStryker'', [[spoiler:Real!Haruna]] shows up as a foe as she had [[spoiler: given her memories of Yuuki to the memory collector to become a stryker and is hired to kill them.]][[/folder]]

[[folder:Western Animation]]* In ''WesternAnimation/TheVentureBrothers'', Rusty doesn't remember Hector Molina, his best friend throughout his childhood, at all when he finds him in the Compound.** Even though Hector was working for him. [[JerkAss Then he fires him]].** In the Season 5 episode "SPHINX Rising", [[spoiler:The Monarch finds a picture of himself and Dr. Venture as young boys playing together. The Monarch is ''extremely'' visibly distressed by this.]]--->[[spoiler:"I don't remember any of this!"]][[/folder]]----